Dark Oxygen: Why has the Earth not run out of Oxygen? Scientists have discovered that the deep depths of the oceans seemingly are a source of oxygen replenishment. See:
https://www.msn.com/en-us/news/us/scientists-say-they-found-oxygen-where-it-shouldn-t-be-now-the-hunt-is-on-for-more-answers/ar-AA1xoRp1?ocid=msedgdhp&pc=DCTS&cvid=a48e9733898844e29367c55d9ea6713b&ei=21